Tibial trialing assembly and method of trialing a tibial implant

ABSTRACT

A trialing assembly for use during knee replacement procedures to determine size and position of a tibial plate implant as well as the size and thickness of the articular surface prior to implantation of the implant. The trialing assembly includes a broaching plate having a tibia engaging bottom surface adapted for placement atop a tibia and an opposite top surface, the bottom and top surfaces extending between an anterior edge and a posterior edge of the broaching plate. The broaching plate includes an anterior rail and a posterior rail protruding superiorly from the top surface and extending along the anterior and posterior edges, respectively. A trialing plate is configured to removably fit atop the broaching plate between the anterior and posterior rails. The trialing plate includes an engagement member extending from a superior surface of the trialing plate and adapted to engage with an articular surface provisional.

PRIORITY REFERENCE

This application claims the benefit of priority under 35 U.S.C. §119(e)to provisional application Ser. No. 60/653,902, filed in the name ofKristina J. Morley et al. on Feb. 17, 2005 and entitled TIBIAL TRIALINGASSEMBLY AND METHOD OF TRIALING A TIBIAL IMPLANT.

BACKGROUND

The present invention relates to trialing devices used during kneereplacement procedures to size and prepare a resected tibia forreceiving a tibial implant and to evaluate the stability and kinematicperformance of the articular surface provisional prior to implantationof the tibial implant.

Generally, the knee is the joint between the femur and the tibia. Theknee joint is formed of a pair of condyles located at the distal portionof the femur, a tibial plateau located at the proximal end of the tibiaand shaped to mate with the pair of condyles, and a pair of meniscipositioned between the tibial plateau and the condyles. The femur andthe tibia are connected by ligaments, which provide stability to theknee. Such ligaments include the posterior cruciate ligament (PCL), thelateral collateral ligament, the medial collateral ligament, and theanterior cruciate ligament. Significant disease of, or trauma to, theknee may warrant replacement of the knee with a prosthetic knee (kneeimplant).

A prosthetic total knee joint generally includes a femoral component anda tibial component. The tibial component typically includes a tibialtray or plate and a prosthetic bearing insert. The tibial tray oftenincludes a stem, which extends from the bottom of the tray and is sizedfor insertion into the tibia. In some knee implants, the bearing insertmay be fixed to the tibial tray such that the bearing insert is immobilerelative to the tibial tray. These knee implant designs are oftenreferred to as “fixed bearing” designs. In other knee implants, thebearing insert is movably fixed to the tibial tray thereby allowing thebearing insert to move relative to the tibial tray. These knee implantdesigns are typically referred to as “mobile bearing” designs.

During mobile bearing knee replacement surgery, the surgeon firstprepares the proximal end of the tibia by resecting the proximal tibiaor, in the case of revision, removing the damaged tibial componentsprior to resecting the proximal tibia. After the tibia is prepared, atibial sizing plate is aligned and placed on the resected tibia, andchecked for size. After the proper sizing plate is selected and theoptimal location is determined, the sizing plate is fixed in position onthe resected tibia by inserting pins through the sizing plate and intothe resected tibia. The pins generally have cap heads that remainextended above the surface of the sizing plate so that the pins can beextracted upon completion of the trial. Next, the surgeon selects anarticular surface provisional, which is modeled in shape and designafter the bearing insert of the tibial component that the surgeonproposes to implant. The surface provisional is then engaged with thesizing plate. With the articular surface provisional in place, thesurgeon then performs trialing procedures to test the fit and functionof the articular surface provisional. Such trialing procedures mayinclude measuring the flexion and extension gaps, and conducting rangeof motion tests, during which the anterior/posterior and medial/lateralstability and movement may be tested. These trialing procedures help thesurgeon determine the proper sized bearing insert. The surgeon mayrepeat the trialing procedures with different sized provisionals untilthe desired results are achieved.

Next, the surgeon removes the pins and the sizing plate. A broachingplate is then positioned and carefully aligned on the resected tibiasuch that pin holes in the broaching plate are aligned with the pinholes created in the tibia by the mounting of the sizing plate. Oncealigned, the broaching plate is pinned in place. With the broachingplate in place, a drill/broach guide is engaged with the upper surfaceof the broaching plate and the proximal tibia is drilled and/or broachedto accommodate the tibial stem of the tibial tray.

There is a need for a tibial trialing device that simplifies andminimizes the steps of knee replacement surgery.

SUMMARY

The present invention provides a trialing assembly for use during kneereplacement procedures to prepare and size a resected tibia forreceiving a tibial implant and to evaluate the stability and kinematicperformance of the articular surface provisional prior to implantationof the tibial implant. In one form, the trialing assembly includes abroaching plate having an outer periphery substantially conforming tothe resected tibia. The broaching plate includes a bottom surfaceadapted for placement atop the resected tibia and an opposite topsurface. The bottom and top surfaces extend substantially between theouter periphery. The broaching plate includes a plurality of alignmentrails protruding superiorly from the top surface and extending along atleast a portion of the outer periphery. A trialing plate is configuredto removably fit atop the broaching plate between the plurality ofalignment rails. The trialing plate has a superior surface and a bossextending superiorly from the superior surface. The boss is adapted toengage with an articular surface provisional.

In another form, the trialing assembly includes a broaching plate havingan outer periphery, a bottom surface adapted for placement atop theresected tibia and an opposite top surface. The bottom and top surfacesextend substantially between the outer periphery. A trialing plate isremovably disposed atop the broaching plate and overlies substantiallyall of the top surface. The trialing plate includes a boss extendingsuperiorly from the superior surface of the trialing plate. The boss isadapted to engage with the articular surface provisional.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective view of a tibial trialing assembly according toone embodiment of the present invention;

FIG. 1A is a sectional view of the tibial trialing assembly taken alongline 1A-1A of FIG. 1;

FIG. 2 is a perspective view of the broaching plate of the tibialtrialing assembly of FIG. 1;

FIG. 3 is a perspective view of the trialing plate of the tibialtrialing assembly of FIG. 1;

FIG. 4 is an exploded perspective view of the tibial trialing assemblyfitted onto a resected tibia;

FIG. 5 is a side view of the tibial trialing assembly of FIG. 1;

FIG. 6 is an exploded perspective view of the broaching plate of thetibial trialing assembly of FIG. 1 fitted onto a resected tibia andcooperating with a drill and drill guide;

FIG. 7 is a perspective view of a disassembled tibial trialing assemblyaccording to another embodiment of the present invention; and

FIG. 8 is a perspective view of a tibial trialing assembly according toanother embodiment of the present invention;

FIG. 9 is a perspective view of the broaching plate of the tibialtrialing assembly of FIG. 8;

FIG. 10 is a perspective view of the trialing plate of the tibialtrialing assembly of FIG. 9;

FIG. 11 is another perspective view of the trialing plate of FIG. 10;

FIG. 12 is a perspective view of a disassembled tibial trialing assemblyaccording to another embodiment of the present invention;

FIG. 13 is a perspective view of the broaching plate of the trialingassembly of FIG. 12;

FIG. 14 is an end view of the broaching plate of FIG. 13;

FIG. 15 is a perspective view of the trialing plate of the trialingassembly of FIG. 12;

FIG. 16 is a perspective view of a provisional tibial base plate inaccordance with one embodiment of the present invention;

FIG. 17 is another perspective view of the provisional tibial base plateof FIG. 16;

FIG. 18 is a perspective view of a trialing plate according to anotherembodiment of the present invention;

FIG. 19 is a side view of the trialing plate of FIG. 18;

FIG. 20 is a top perspective view of a broaching plate according toanother embodiment of the present invention; and

FIG. 21 is a bottom perspective view of the broaching plate of FIG. 20.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the drawings representembodiments of the present invention, the drawings are not necessarilyto scale and certain features may be exaggerated in order to betterillustrate and explain the present invention. Although theexemplification set out herein illustrates embodiments of the invention,in several forms, the embodiments disclosed below are not intended to beexhaustive or to be construed as limiting the scope of the invention tothe precise forms disclosed.

DETAILED DESCRIPTION

The present invention will now be described with reference to theattached figures. The description below may include references to thefollowing terms: anterior (at or near the front of the body, as opposedto the back of the body); posterior (at or near the back of the body, asopposed to the front of the body); lateral (at or near the side of thebody, farther from the midsagittal plane, as opposed to medial); medial(at or near the middle of the body, at or near the midsagittal plane, asopposed to lateral); proximal (toward the beginning, at or near the headof the body, as opposed to distal) and distal (further from thebeginning, at or near the foot of the body, as opposed to proximal).

Referring first to FIG. 1, tibial trialing assembly 10 according to oneembodiment of the present invention is shown. Trialing assembly 10generally includes broaching plate 12 and trialing plate 14. Referringnow to FIGS. 1, 1A and 2, broaching plate 12 includes an outer peripheryshaped to conform to a resected tibia. The outer periphery includesanterior edge 16 and opposing posterior edge 18. Broaching plate 12 alsoincludes bottom surface 22 and opposing top surface 24. Bottom and topsurfaces 22, 24 are substantially flat and extend between anterior edge16 and posterior edge 18. As is discussed in further detail below,broaching plate 12 is sized for placement atop a resected tibia.Accordingly, bottom surface 22 is configured for placement on, andcontact with, the resected tibia. In addition, a portion of posterioredge 18 curves inward toward anterior edge 16 to form PCL cutout 20. PCLcutout 20 is configured to accommodate the patient's posterior cruciateligament when broaching plate 12 is placed atop the resected tibia.

Referring still to FIGS. 1 and 2, broaching plate 12 includes a pair ofopposing alignment rails 26, 28 protruding superiorly from top surface24. Pair of opposing alignment rails 26, 28 includes anterior rail 26,which extends along a portion of anterior edge 16. Posterior rail 28extends along a portion of posterior edge 18. Particularly, posteriorrail 28 extends along and around PCL cutout 20 of posterior edge 18.Anterior rail 26 and posterior rail 28 include superior surfaces 26 a,28 a, respectively.

Referring now to FIG. 2, pin holes 30 extend through broaching plate 12from top surface 24 to bottom surface 22. Pin holes 30 are adapted toreceive pins 36 (FIG. 4) or any other fasteners including screws ornails, as further discussed below. Broaching plate 12 includes broachreceiving opening 32 extending through broaching plate 12. As discussedin further detail below, broach receiving opening 32 is sized andconfigured to allow the passage of a drill and/or a broach. Alignmentopenings 34 extend through broaching plate 12 and are adapted to receivealignment pegs 64 (FIG. 6) of broach impactor and/or drill guide 60(FIG. 6), as is discussed in further detail below.

Referring to FIGS. 1 and 2, broaching plate 12 includes anterior tabs 40protruding anteriorly from anterior edge 16. Anterior tabs 40 defineopenings 40 a which together with tabs 40 are adapted to engage with ahandle (not shown) to facilitate the positioning of broaching plate 12on the resected tibia, as described in U.S. patent application Ser. No.10/938,979, entitled Tibial Sizing Apparatus and Method filed Sep. 9,2004, assigned to the assignee of the present application and herebyincorporated by reference. Broaching plate 12 further includes posteriortabs 38 extending posteriorly from posterior edge 18. Posterior tabs 38define openings 38 a, which are configured to receive drop down screws(not shown). Posterior tabs 38, openings 38 a, and drop down screwscooperate, as described in the above-incorporated U.S. patentapplication Ser. No. 10/938,979, to further aid in the positioning ofbroaching plate 12 on the resected tibia.

Broaching plate 12 may be formed of any surgical grade rigid material.For example, broaching plate 12 may be formed of cobalt chromium,stainless steel, titanium, and/or alloys thereof. Broaching plate 12 maybe made available in various sizes to accommodate various sized tibias.

Turning now to FIGS. 1 and 3, trialing plate 14 includes substantiallyflat superior surface 42 and substantially flat, opposing inferiorsurface 44. Head receiving openings 46 extend through trialing plate 14from superior surface 42 to inferior surface 44 and are adapted toaccommodate head 36 a of pins 36 (FIG. 4), as further discussed below.

Trialing plate 14 includes articular surface provisional engagementmember or boss 48 protruding superiorly from superior surface 42. Asdiscussed below, boss 48 has an elliptically shaped cross-section and isconfigured to engage with an articular surface provisional.Alternatively, engagement member or boss 48 may have a variety of shapesand sizes to accommodate engagement with various designs of surfaceprovisionals. Furthermore, trialing plate may comprise more than onearticular surface provisional engagement member or boss. Central bore 50extends in the superior/inferior direction through boss 48 and trialingplate 14. Bore 50 is adapted to allow the passage of fastener 54 (FIG.4), as further discussed below. Boss 48 is defined by outer perimetricalwall 51, and includes a trialing plate removal element, which in thisembodiment is in the form of groove 52 cut into wall 51. Similar tobroaching plate 12, trialing plate 14 may be formed of any surgicalgrade rigid material. For instance, trialing plate 14 may be formed ofcobalt chromium, titanium, stainless steel and/or alloys thereof.

Turning now to FIGS. 1-3 and 5, trialing plate 14 is sized andconfigured to removably fit atop broaching plate 12 between anterior andposterior rails 26, 28. When trialing plate 14 is so positioned atopbroaching plate 12, trialing plate 14 overlies substantially all of topsurface 24 of broaching plate 12. In addition, as illustrated in FIGS.1A and 5, when trialing plate 14 is properly positioned atop broachingplate 12, superior surface 42 of trialing plate 14 is substantiallylevel, or flush, with superior surfaces 26 a and 28 a of respectiveanterior and posterior rails 26, 28 to provide a smooth surface on whichthe articular surface provisional can move. As shown in FIGS. 1A and 5,when trialing plate 14 is positioned atop broaching plate 12, inferiorsurface 44 of trialing plate 14 is supported on top surface 24 ofbroaching plate 12 such that inferior surface 44 is non-level withbottom surface 22. Referring specifically to FIG. 5, when assembled,trialing assembly has height H extending from level superior surfaces 26a, 28 a, 42 to bottom surface 22. Height H is sized to correspond to theheight of the tibial tray of the tibial implant to be installed.

Turning now to FIG. 4, use of tibial trialing assembly 10 will now bedescribed. After resecting the patient's tibia T, the surgeon selects atibial trialing assembly 10 that most closely corresponds in size to theproximal surface of tibia T. As noted above, this trialing assembly 10will have a width equal to the tibial tray of the tibial implant thesurgeon proposes to use. Next, broaching plate 12 of trialing assembly10 is placed on the resected surface of tibia T. Broaching plate 12 isthen secured in position on tibia T by inserting pins 36 through pinholes 30 of broaching plate 12 and into tibia T. Heads 36 a of pins 36protrude superiorly from holes 30 such that pins 36 may be easilyremoved later. Referring now to FIGS. 1, 1A and 4, once broaching plate12 is secured to tibia T, trialing plate 14 is positioned atop broachingplate 12 between anterior and posterior rails 26, 28. In this position,head receiving openings 46 of trialing plate 14 are aligned with pinholes 30 of broaching plate 12. Protruding heads 36 a of pins 36 arereceived in head receiving openings 46 thereby preventing heads 36 afrom interfering with the flush placement of inferior surface 44 oftrialing plate 14 against top surface 24 of broaching plate 12.

When trialing plate 14 is properly positioned atop broaching plate 12,trialing plate 14 overlies substantially all of top surface 24 ofbroaching plate 12 to provide a smooth, un-interrupted surface on whichthe surface provisional may articulate. Once trialing plate 14 isflushly positioned atop broaching plate 12, anterior and posterior rails26, 28 cooperate to prevent the movement of trialing plate 14 along theplane of top surface 24 in the medial/lateral and anterior/posteriordirections. Furthermore, as illustrated in FIGS. 1, 1A, 4 and 5, when inposition atop broaching plate 12, superior surface 42 of trialing plate14 is level with superior surfaces 26 a, 28 a of respective anterior andposterior rails 26, 28. As illustrated in FIGS. 1A and 5, inferiorsurface 44 of trialing plate 14 is supported by top surface 24 ofbroaching plate 12 and, therefore, is spaced apart from bottom surface22 of broaching plate 12. Trialing plate 14 may be secured in positionby driving fastener 54 through bore 50 and into resected tibia T.

Referring now to FIG. 4, a selected articular surface provisional (notshown) may now be engaged with boss 48 and conventional trialing andsizing procedures may be performed. Boss 48 is configured to provide anaxis of rotation for trialing articular surface provisionals modeledafter mobile bearing implant designs. The surgeon may trial severaldifferent sized articular surface provisionals. Once the surgeon hascompleted the trialing and sizing procedures and has determined theproper size of bearing insert, trialing plate 14 is removed by engaginggroove 52 of boss 48 with a tool and pulling trialing plate 14 andfastener 54 from tibia T, exposing broaching plate 12 still aligned andin place on tibia T. The combined height H of broaching plate 12 andtrialing plate 14 is substantially equivalent to the tibial plateimplant height to mimic the function of the tibial plate during trialingof a selected surface provisional. However, it should be noted that insome cases the combined height H need not be equivalent to the height ofthe tibial plate. For instance, if the selected articular surfaceprovisional is configured to have a height (thickness) greater than thatof the articular surface implant, combined height H may be thinner thanthe height of the tibial plate. Conversely, if the selected articularsurface provisional is configured to have a height (thickness) less thanthat of the articular surface implant, combined height H may be greaterthan the height of the tibial plate. In other words, the combined heightof the trialing assembly and the articular surface provisional isequivalent to the combined height of the tibial plate implant and thearticular surface implant.

Turning now to FIG. 6, the surgeon can now prepare the tibia forreceiving the stem of the tibial tray. The surgeon inserts alignmentpegs 64 of drill guide 60 into alignment openings 34. Drill 62 may thenbe driven through guide 60, then through broach opening 32 and intotibia T to create a passage in tibia T for the acceptance of the stem ofthe tibial tray. Drill 62 and guide 60 are then removed. Finally,broaching plate 12 is then removed, leaving the prepared, resected tibiaready to receive the tibial tray.

Turning now to FIG. 7, another embodiment is illustrated. Tibialtrialing assembly 110 includes broaching plate 112 and trialing plate114. Broaching plate 112 includes all of the features of broaching plate12 (FIG. 2) with the addition of augment holes 141. Trialing plate 114includes all of the features of trialing plate 14 (FIG. 3) with theaddition of augment holes 142. Augment holes 141 and 142 are adapted toreceive an alignment fastener (not shown) for attaching conventionalaugment provisionals to trialing assembly 110. Exemplary augmentprovisionals that may be used with broaching plate 112 include NEXGEN®augment provisionals by Zimmer, Inc. of Warsaw, Ind.

Referring now to FIGS. 8-11, tibial trialing assembly 210 according toanother embodiment is illustrated. Tibial trialing assembly 210 includesbroaching plate 212 and trialing plate 214. As shown in FIGS. 8 and 9,broaching plate 212 includes an outer periphery shaped to conform to aresected tibia. The outer periphery includes anterior edge 216 andposterior edge 218. Unlike broaching plate 12 of trialing assembly 10(FIG. 1), posterior edge 218 does not include a PCL cut out portion.Broaching plate 212 includes a pair of opposing alignment rails 226, 228protruding superiorly from the top surface of broaching plate 212. Pairof opposing alignment rails 226, 228 includes anterior rail 226, whichextend along a portion of anterior edge 216, and posterior rail 228,which extends along a portion of posterior edge 218. Pin holes 230extend through broaching plate 212 and are adapted to receive fasteners(such as pins 36 in FIG. 4) for securing broaching plate 212 to thetibia. Broaching plate 212 also includes broach opening 232, which issized and configured to allow the passage of a drill and/or broach.

Turning now to FIGS. 8, 10 and 11, trialing plate 214 is substantiallyflat and is sized to fit over broaching plate 212 between anterior andposterior rails 226, 228. Trialing plate 214 includes superior surface242 and opposing inferior surface 244. Pin head receiving openings 246extend through trialing plate 214 from superior surface 242 to opposinginferior surface 244. Openings 246 are adapted to accommodate the headof fasteners received within holes 230 of broaching plate 212. Trialingplate 214 includes engagement member or boss 248 protruding superiorlyfrom superior surface 242. As noted above, the boss may have a varietyof shapes and sizes. For instance, in the present embodiment, boss 248has a circular cross-sectional shape, thereby demonstrating at least onealternative shape.

Although the embodiments discussed above show a pair of opposinganterior and posterior rails, alignment rails could, alternatively,include any number of rails positioned at any location along the outerperiphery. For instance, the alignment rails may include two opposingrails, one located at the medial edge of the outer periphery and theother at the lateral edge of the outer periphery. In another example,the alignment rails may include three rails spaced apart along the outerperiphery. In fact, it is possible to have a single rail extending alonga portion of the periphery enough to limit the movement of the trialingplate when mounted atop the broaching plate. Furthermore, the alignmentrail or rails need not be positioned on the periphery of the plate. Itis also possible to have no alignment rails, instead using alignmentmembers, such as pegs extending from one of the trialing plate orbroaching plate and mating with alignment holes in the other of thetrialing plate and broaching plate. Alternatively, the pin heads used tofix the broaching plate to the tibia could be used in conjunction withthe head receiving openings in the trialing plate to align the trialingplate on the broaching plate. It should also be noted that the alignmentrails could be alternatively disposed on the inferior surface of thetrialing plate and could engage the outer periphery of the broachingplate such that broaching plate positioned between the alignment railsof the trialing plate.

For example, FIGS. 12-15 illustrate an embodiment having no alignmentrails. Tibial trialing assembly 310 includes broaching plate 312 andtrialing plate 314. Broaching plate 312 includes an outer peripheryshaped to conform to a resected tibia. The outer periphery includesanterior edge 316 and posterior edge 318. Broaching plate 312 alsoincludes pin holes 330, which are adapted to receive fasteners (such aspins 36 in FIG. 4) for securing broaching plate 312 to the tibia.Broaching plate 312 also includes broach opening 332, which is sized andconfigured to allow the passage of a drill and/or broach. Broachingplate 312 also defines a pair of peg holes 334.

Turning to FIGS. 12 and 15, trialing plate 314 is sized and configuredto fit over broaching plate 312 and includes inferior surface 344 andopposing superior surface 342. Boss 348 protrudes superiorly fromsuperior surface 342 and is adapted to engage with trialing surfaceprovisionals. Trialing plate 314 also include pegs 346 extending frominferior surface 344. Pegs 346 are sized and positioned to align withand extend into peg holes 334 of broaching plate 312 when trialing plate314 is seated on broaching plate 312. Pegs 346 serve to maintaintrialing plate's 314 position atop broaching plate 312 and to preventtrialing plate 314 from sliding off of broaching plate 312. It should beunderstood that pegs 346 may be alternatively disposed on the topsurface of broaching plate 312, while peg holes 334 may be alternativelydisposed in the inferior surface of trialing plate 314.

Also, as shown in the embodiments described above, superior surface ofthe trialing plate is level with the superior surfaces of the rails.Alternatively, superior surface 42 of trialing plate 14 may be proud, orraised, with respect to superior surfaces 26 a and 28 a of anterior andposterior rails 26, 28 to provide a smooth surface and to prevent rails26, 28 from interfering with the movement of the articular surfaceprovisional.

Referring to FIGS. 16-19, provisional base plate 412 and complementarytrialing plate 414 according to one embodiment of the present inventionwill now be described. Referring specifically to FIGS. 16 and 17,provisional base plate 412 according to the present invention isillustrated. Provisional base plate 412 is adapted to be mounted on theprepared end of the tibia after the passage has been drilled or broachedinto the tibia using a broaching plate as described above. Provisionalbase plate 412 includes anterior edge 416 and opposing posterior edge418. Provisional base plate 412 also includes PCL cut out 420 atposterior edge 418. Provisional base plate includes opposing inferiorand superior surfaces 422, and 424, respectively, which extend betweenanterior and posterior edges 416, 418. Pair of opposing alignment rails426, 428 protrudes superiorly from superior surface 424. Pair ofopposing alignment rails 426, 428 includes anterior rail 426, whichextends along a portion of anterior edge 416, and posterior rail 428,which extends along a portion of posterior edge 418. Notch 427 is formedin anterior rail 426. Provisional base plate 412 also includes stem 430extending inferiorly from inferior surface 422. Stem 430 is configuredto be received in the passage, which was created in the tibia asdescribed above. Stem 430 includes central bore 434 extendingconcentrically therein. Bore 434 may be configured to receive a stemextension (not shown) as needed. Alternatively, bore 434 may be threadedand adapted to receive an extraction tool, such as a threaded rod orhandle, for extracting provisional base plate 412 from the tibia. Wingsor flanges 432 extend radially outward from stem 430 and serve to aid inanchoring stem 430 in the passage in the tibia. Provisional base plate412 may also be equipped with a magnet operable at superior surface 424to hold trialing plate 414 in place atop provisional base plate 412.

Turning now to FIGS. 18 and 19, trialing plate 414 is illustrated.Trialing plate 414 includes superior surface 442 and opposing inferiorsurface 444. Head receiving openings 446 extend through trialing plate414 from superior surface 442 to inferior surface 444. Boss 448 extendsupwardly from superior surface 442 and, as suggested above, demonstratesyet another shape and size of the boss. As illustrated in FIG. 18, boss448 is curved to provide limited arc of motion of the articular surfaceprovisional (not shown) with which boss 448 mates. Accordingly, trialingplate 414 is configured to mimic the surface of a tibial base plate of aknee implant for use in the left knee. Alternatively, trialing plate 414could be adapted to mimic the surface of a tibial base plate of rightknee implant by providing a boss having a shape of a mirror-image tothat of boss 448.

Tab 453 (FIG. 18) extends from an anterior edge of trialing plate 414and is configured to mate with notch 427 of provisional base plate 412,shown in FIG. 16. Trialing plate 414 is substantially flat and is sizedto fit over provisional base plate 412 between anterior and posteriorrails 426, 428, such that superior surface 442 of trialing plate 414 issubstantially level with superior surfaces 426A, 428A of correspondinganterior posterior rails 426, 428. When trialing plate 414 is positionedover provisional base plate 412, tab 453 is received in notch 427 torestrict movement of trialing plate 414 in the medial-lateral direction.Tab 453 also facilitates removal of the trialing plate from thebroaching plate and provisional plate. Anterior and posterior rails 426,428 prevent movement of trialing plate 414 in the anterior-posteriordirection. Once trialing plate 414 is properly positioned atopprovisional base plate, an articular surface provisional (not shown) maynow be engaged with boss 448 and conventional trialing and sizingprocedures may be performed.

Trialing plate 414 is adapted to also mate with broaching plate 512,shown in FIGS. 20 and 21. Broaching plate 512 includes an outerperiphery shaped to conform to a resected tibia. The outer peripheryincludes anterior edge 516 and opposing posterior edge 518. Broachingplate 512 also includes bottom surface 522 and opposing top surface 524.Bottom and top surfaces 522, 524 are substantially flat and extendbetween anterior edge 516 and posterior edge 518. Broaching plate 512 issized for placement atop a resected tibia. Accordingly, bottom surface522 is configured for placement on, and contact with, the resectedtibia. In addition, a portion of posterior edge 518 curves inward towardanterior edge 516 to form PCL cutout 520. PCL cutout 520 is configuredto accommodate the patient's posterior cruciate ligament when broachingplate 512 is placed atop the resected tibia.

Referring still to FIGS. 20 and 21, broaching plate 512 includes a pairof opposing alignment rails 526, 528 protruding superiorly from topsurface 524. Pair of opposing alignment rails 526, 528 includes anteriorrail 526, which extends along a portion of anterior edge 516, andposterior rail 528, which extends along a portion of posterior edge 518.Particularly, posterior rail 528 extends along and around PCL cutout 520of posterior edge 518. Anterior rail 526 and posterior rail 528 includesuperior surfaces 526 a, 528 a, respectively. Pin holes 530 extendthrough broaching plate 512 from top surface 524 to bottom surface 522.Pin holes 530 are adapted to receive pins (such as pins 36 shown in FIG.4) or any other fasteners including screws or nails, as furtherdiscussed below. Broaching plate 512 includes broach receiving opening532 extending through broaching plate 512. Broach receiving opening 532is sized and configured to allow the passage of a drill and/or a broach.Broaching plate also includes notch 527 formed in anterior rail 526.

Broaching plate 512 and trialing plate 414 are used in a manner similarto that described above with respect to broaching plate 12 and trialingplate 14. Broaching plate 512 is secured to the resected surface of thetibia by inserting pins through pin holes 530. Trialing plate 414 isplaced over broaching plate 512 and is positioned between rails 526, 528such that the heads of the pins are received in head receiving openings446 of trialing plate 414 and tab 453 is positioned in notch 527. Whenso positioned, superior surface 442 of trialing plate 414 is level withsuperior surfaces 526 a, 528 a of anterior and posterior rails 526, 528.The assembly of broaching plate 512 and trialing plate 414 may be usedto trial an articular surface provisional in a manner similar to thatdescribed above with respect to tibial trialing assembly 10.

Although the embodiments shown in the drawings and discussed above areused in the sizing and trialing of knee implants, it is contemplatedthat the present invention could be adapted for use in sizing andtrialing other implants, including elbows and ankles.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

1. A trialing assembly for use during a knee replacement procedure tosize and prepare a resected tibia for receiving a tibial implant and totrial an articular surface provisional, said trialing assemblycomprising: a broaching plate having an outer periphery, said broachingplate including a bottom surface adapted for placement atop the resectedtibia and an opposite top surface, and a plurality of alignment railsprotruding from said top surface, each alignment rail extending adjacentat least a portion of said outer periphery; and a trialing plateremovably positionable atop said broaching plate between said pluralityof alignment rails, said trialing plate having a superior surface and anarticular surface provisional engagement member extending superiorlyfrom said superior surface.
 2. The trialing assembly of claim 1 whereinsaid plurality of alignment rails includes an anterior rail extendingadjacent an anterior portion of said outer periphery and a posteriorrail extending adjacent a posterior portion of said outer periphery. 3.The trialing assembly of claim 1 wherein said trialing plate overliessubstantially all of said top surface of said broaching plate when saidtrialing plate is positioned atop said broaching plate.
 4. The trialingassembly of claim 1 wherein said broaching plate includes at least onefastener hole configured for receipt of a fastener therethrough forengagement with the resected tibia.
 5. The trialing assembly of claim 4wherein said fastener includes a head, said head engaging, and extendingsuperiorly from, said top surface of said broaching plate when saidfastener is received within said at least one fastener hole, saidtrialing plate including at least one opening, said at least one openingaligned with said at least one fastener hole and receiving said fastenerhead when said trialing plate is positioned atop said broaching plate.6. The trialing assembly of claim 1 wherein said engagement memberincludes a trialing plate removal element.
 7. The trialing assembly ofclaim 1 wherein each of said plurality of alignment rails includes anupper surface, said superior surface of said trialing plate beingsubstantially level with said upper surface of each of said plurality ofalignment rails when said trialing plate is positioned atop saidbroaching plate.
 8. A trialing assembly for trialing an articularsurface provisional prior to implantation of the tibial implant on aresected tibia, the trialing assembly comprising: a broaching platehaving an outer periphery surrounding a bottom surface adapted forplacement atop the resected tibia and an opposite top surface; and atrialing plate removably disposed atop said broaching plate andoverlying substantially all of said top surface, said trialing plateincluding an articular surface provisional engagement member extendingsuperiorly from a superior surface of said trialing plate.
 9. Thetrialing assembly of claim 8 wherein said member includes a trialingplate removal element.
 10. The trialing assembly of claim 9 wherein saidmember includes an outer wall, and said trialing plate removal elementincludes a groove within said outer wall.
 11. The trialing assembly ofclaim 8 wherein said broaching plate includes at least one alignmentrail protruding superiorly from said top surface.
 12. The trialingassembly of claim 11 wherein said at least one alignment rail includesan anterior rail extending along an anterior portion of said outerperiphery and a posterior rail extending along a posterior portion ofsaid outer periphery.
 13. The trialing assembly of claim 8 furthercomprising a provisional base plate having a base plate peripherysurrounding an upper surface and an opposite lower surface, said lowersurface adapted for placement atop the resected tibia, said provisionalbase plate having a stem projecting from said lower surface and adaptedfor insertion into the resected tibia, said base plate having at leastone alignment rail projecting from said upper surface, said trialingplate removably positionable atop said provisional base plate andengagable with said at least one alignment rail to prevent movement ofsaid trialing plate relative said base plate along a plane of the uppersurface of said base plate.
 14. The trialing assembly of claim 1 whereinone of said plurality of alignment rails includes a notch and saidtrialing plate includes a tab, said tab configured to be received insaid notch when said trialing plate is positioned atop said broachingplate.
 15. The trialing assembly of claim 8 wherein said trialing plateincludes an inferior surface opposite said superior surface, and whereinone of said inferior surface of said trialing plate and said top surfaceof said broaching plate includes at least one alignment member extendingoutwardly therefrom, and the other of said inferior surface of saidtrialing plate and said top surface of said broaching plate includes atleast one alignment member opening, said at least one alignment memberopening receiving said at least one alignment member.
 16. The trialingassembly of claim 8 wherein said broaching plate includes at least onefastener hole and said trialing plate includes a head receiving openingaligned with each of said at least one fastener holes.
 17. The trialingassembly of claim 8 wherein said trialing plate includes a central boreextending through said boss and said trialing plate and configured toreceive a fastener therethrough to fix said trialing plate to theresected tibia.
 18. The trialing assembly of claim 8 wherein each ofsaid broaching plate and trialing plate includes a plurality of augmentholes each adapted to mate with an augment provisional.
 19. The trialingassembly of claim 8 wherein one of said trialing plate and saidbroaching plate includes at least one alignment rail, said at least onealignment rail engaging the other of said trialing plate and saidbroaching plate to restrict movement of said trialing plate relativesaid broaching plate along a plane of said top surface.
 20. A trialingassembly for trialing an articular surface provisional, the trialingassembly comprising: a broaching plate having a bottom surface adaptedfor placement atop the resected tibia and an opposite top surface; and atrialing plate removably disposed atop said broaching plate andoverlying substantially all of said top surface, said trialing platehaving an inferior surface adapted for placement atop said top surfaceand an opposite superior surface, said trialing plate including anengagement member extending superiorly from said superior surface, saidengagement member adapted to engage with said surface provisional,wherein one of said broaching plate and said trialing plate including atleast one peg opening, the other of said broaching plate and saidtrialing plate includes at least one peg extending therefrom, said atleast one peg received within said at least one peg opening.